A watch including means for detecting a power shortage for the motor is known particularly from Patent document No. WO 98/33098. This document presents an electronic watch having hands driven by a motor and controlled by electronic means containing time related data, a power source and means for detecting power shortage of this source. In the event of power shortage, the hands are brought to and kept at reference positions programmed in advance in the electronic means.
This watch has, however, some drawbacks. Indeed, the hands of the watch are the reflection of the electronic means counter value. This is why it is necessary to bring the hands into a reference position, when there is a power shortage, to force the value of this counter to a reference value programmed before the watch is set into operation. Thus, this counter synchronised with the hands can no longer be used as a time counter. It is thus necessary to have a second counter, which counts time during a power shortage. However, during normal operation of the watch, which represents most of the operating time, the two counters contain the same values. These two counters unnecessarily complicate the electronic means of the watch.
It is thus a main object of the invention to overcome the drawbacks of the aforementioned prior art by providing an electronic watch which includes simplified electronic means that do not require any reference value to be programmed in order to reset the time following a power shortage.